Unfortunately, the United States' economy and lifestyle are based on having a steady and inexpensive petroleum hydrocarbon supply available for import from foreign sources. Consequently, this petroleum supply and demand dynamic will siphon more and more hard capital and jobs from the domestic economy as the century progresses due to diminishing crude oil reserves. Earth's crude oil reserves are large but finite in volume. Many scientists predict that crude oil production from proven reserves will peak within this century. The decline in production will adversely affect the United States' oil-based economy and lifestyle. Due to impending fossil fuel supply issues this century, the U.S. continues to shift significant resources to identify realistic and economically viable avenues to produce a domestic renewable hydrocarbon equivalent.
Initially, U.S. scientists focused on using fatty acids from terrestrial plants and animals to make biodiesel fuels. The biodiesel produced is a compatible substitute for fossil fuel diesel but not close to being a robust inexpensive equivalent. The main issues with using terrestrial plant and animal fatty acids are:                These feedstocks are expensive and account for as much as 80% of the fuel's cost. According to Anthony Radich and Rudy Pruszko, the best way to reduce renewable diesel and jet fuel production cost is by lowering feedstock cost. See, e.g., Pruszko, R (2007), “Alternative Feedstocks and Biodiesel Production”, Presented at the Practical Biodiesel Blueprint Conference, Radich, A. (2004); “Biodiesel Performance, Costs, and Use” Energy Information Administration, p 4, Website http://www.eia.doe.gov/oiaf/analysispaper/biodiesel/pdf/biodiesel.pdf, which is hereby incorporated by reference in its entirety.        There are limited quantities of tallow, waste vegetable oil (WVO), and soybeans.        Terrestrial feedstocks cultivation compete with other needs for land and water resources.        Several plant feedstocks are also foods thus increasing the demand on a limited supply.        
In order to address these issues, renewable fuel research has focused on microalgae cultivated in freshwater ponds and bioreactors because of their high yield per hectare as well as their high lipid and protein composition relative to other photoautotrophs. See, e.g., Ingole B S, Parulekar A H, (1995) “Biochemical-Composition Of Antartic Zooplankton From The Indian-Ocean Sector” Indian Journal Of Marine Sciences 24(2): 73-76, which is hereby incorporated by reference in its entirety. The problems with using microalgae produced from land based aquacultures, ponds, and bioreactors are: high capital cost, high fresh water consumption, generates waste streams, not portable, and not easily scalable.
Therefore, a need exists for improved systems and methods for cultivating biomass. A further need exists for improved systems and methods for harvesting and processing biomass.